Hayden and Gilchrist never looked in a hurry but still raced to the target with barely a false shot played.

Hayden finished the match with a huge six over long-on off the occasional bowling of Jehan Mubarak to end with 56 off 37 balls while Gilchrist was never out of second gear and faced just 25 deliveries.

After Gilchrist had won an important toss - batting at 10am in Cape Town in springtime is not a friendly prospect - the Aussie bowlers were on the money throughout.

Brett Lee (2-27) did win a fortunate lbw decision to get the ball rolling with the wicket of Sanath Jayasuriya.

The rest of the Sri Lankan batsmen then found scoring opportunities severely limited with the swing on offer and the ball not quite coming onto the bat.

They generally got out to rash shots, with three catches offered to third man and two to backward point - including a brilliant one-handed take by Michael Clarke.

Brett Lee gets the ball rolling by ousting Sanath Jayasuriya

The highest individual scorer was Mubarak, with 28.

Sri Lanka would have been 11-4 in the fourth over if Brad Hodge had caught Kumar Sangakkara on six, the batsman finally out for 22.

Clark struck consistently, however, the only downside for Australia being another injury for Shane Watson.

The Queensland all-rounder, in for Ricky Ponting (hamstring), was making his first appearance of the tournament.

But he has been dogged by injuries in his international career.

And after Lasith Malinga hoicked the second ball of his final over beyond the rope for Sri Lanka's only six, Watson limped out of the fray.

The over, the 19th of the innings, was completed by Andrew Symonds, who promptly had Chaminda Vaas (21) caught at deep mid-wicket.

And the last wicket fell in the final over - Dilhara Fernando becoming a second victim for Nathan Bracken when he gave the bowler a simple return catch.

Australia captain Adam Gilchrist:"Our fast bowlers were outstanding and created a lot of chances, all of which we took, except one.

"That was important... it would have been difficult chasing any sort of decent target on that sort of wicket.

"We almost got knocked out in the initial stage but are now into the cut-throat part of the competiton.

"A lot of teams would have preferred to see us go out but perhaps they are a little bit nervous now we are still here."

Sri Lanka captain Mahela Jayawardene:"It was a very disappointing effort, especially with the bat.

"We knew it would be tough but we had to make sure we put a few runs on the board for our bowlers to defend.

"It's always a challenge to face these guys - they are setting standards - but we never turned up for the game.

"We need to play more Twenty20 cricket so we can learn to adjust to situations and conditions."